WO2013156953A1

WO2013156953A1 - Process for obtaining biofuel from castor oil

Info

Publication number: WO2013156953A1
Application number: PCT/IB2013/053056
Authority: WO
Inventors: Jorge Daniel PÉREZ; Omar MACCAGLIA
Original assignee: Consejo Nacional de Investigaciones Cientificas y Tecnicas CONICET; Universidad Nacional de Cordoba; Ministerio de Defensa; Inis Biotech LLC
Current assignee: Consejo Nacional de Investigaciones Cientificas y Tecnicas CONICET; Universidad Nacional de Cordoba; Ministerio de Defensa; Inis Biotech LLC
Priority date: 2012-04-18
Filing date: 2013-04-17
Publication date: 2013-10-24
Anticipated expiration: 2014-10-18
Also published as: AR086171A1

Description

PROCESS FOR OBTAINING BIOFUEL FROM CASTOR OIL

Technical field of the invention

The present invention relates to technological field related to fuels obtained from vegetable organic material. It is particularly related to fuels obtained by processing castor oil (ricin oil), processes for its obtaining, and uses in very low temperature conditions.

Background of the invention

Constant growth of energetic demand related to technological development and its expected increase in the future have triggered multiple alert signs in the international community. Fossil fuels, and particularly oil, have reached historic record prices due to a combination of factors: on the one hand, decrease of reserves as a result of oil^'s non-renewable resource nature; on the other hand, due to geopolitical conflicts that generally take place in the main production regions, and which are the result of the strategic value of these resources.

Although what is mentioned above is an objective reality which is directly reflected in the cost of the fuels, the real problem of humanity is the impact on the environment resulting from gas emissions, mainly carbon dioxide and nitrogen oxides which produce the so called "greenhouse effect" and which inevitably leads to global warming.

Upon such scenario, during the past years there has been a strong impulse to the search for alternative energy sources which are environmentally friendly and reduce the collateral effects resulted from the use of fossil fuels. The following documents of the prior art summarize some of the solutions proposed worldwide to the technical problem:

Iva Kubickova^', Mathias Snare, Kari Eranen, Paivi Maki-Arvela, Dmitry Yu. Murzin, Catalysis Today, 106 (2005), 197-200.

K.D. Maher and D.C. Bressler, Bioresource Technology, 98 (12), 2007, 2351-

2368.

On the other hand, the patent US 7.247.739 discloses a method of acid or base - catalyzed esterification and transesterification of fatty acids, such as oils and fats, for example, esters of glycerol with fatty acids, by dispersion of a lower alcohol, specially methyl alcohol, in a starting liquid product.

The Argentinean patent application P07 01 01960, (publication number AR 060775 A1 ) which inventors are the same as those of the present invention, describes a method to process to obtain a biofuel suitable for aviation turbines mixing biodiesel with aeronautic kerosene (JP A1 ).

The patent application US 2012/001 1765 A1 (WO 2010/103223 A1 ) claims a biofuel for aeronautic use based on mixtures of nitriles and esters of fatty acids of low molecular weight (less than C14) to partially replace the aeronautic kerosene.

In the patent application US 201 1/0289828 A1 , it is described the obtaining of a mixture of tri-, di- and mono-glyceride as additive and/or alternative fuel for gasoil with good performance at low temperatures, although regulation CEN 14214 for biofuel sets the maximum limit of these at 0.8 % for monoglycerides and 0.2 % for diglyce rides.

In the midst of important development in obtaining and commercialization of biodiesel at the international and national level, there is a serious problem which consists of the impact that the increase of the biodiesel supply will have on food prices and availability in a world with millions of human beings that suffer severe nutritional issues. This is due to the use of edible oils (mainly, soya bean oils) as raw material of such biodiesel. That is the reason why many research groups make efforts in order to obtain fuels from non-edible oils and/or fats.

Obtaining of ethyl esters from castor oil directly from the seeds is described in the patent application US 2005/001 1 1 12 A1.

The patent application CN 101629088 describes a method of base-catalyzed transesterification of the castor oil with methanol (1 :6) at a temperature from 45 to 65 C° and for a time of 1.5 to 6 hours.

The present invention provides a procedure that presents the following advantages when compared to the documents of the state of the art: simpler, with shorter reaction time, low energy consumption since it is practically carried out at room temperature, and high performance/yield for obtaining FAME (fatty acids methyl esters) from castor oil (ricin oil) and its treatment to make it suitable as a partial replacement of Jet A1 and Antarctic Fuel Oil. Likewise, this FAME is suitable as partial replacement of gasoil in low temperature regions. Furthermore, it presents steps of purification carried out after the dilution of raw and dry biodiesel with JP A1 , which allow to obtain a new aeronautic turbo fuel in a simple and inexpensive way.

Brief description of the invention

The process for obtaining biofuel from castor oil, which is the main object of the present invention, comprises the following steps: a- Reacting by transesterification commercial castor oil, methanol and sodium hydroxide previously dissolved in said methanol at a temperature less than 40C°, preferably less than 30C° and during a maximum time of 60 minutes, where the maximum relation between said methanol with respect to said castor oil is preferably up to 1 :5 (oil volume:methanol volume),

b- decanting,

c- removing glycerin which is the lower phase,

d- neutralizing with acid, preferably with glacial acetic acid,

e- washing with water in at least two steps, preferably incorporating it as an aerosol from above avoiding thus an excessive emulsification,

f- removing the lower aqueous phase from the last washing in order to obtain raw biodiesel,

g- eliminating the remaining water and the excess of methanol by vacuum distillation and obtaining raw and dry biodiesel, preferably with a yield of at least 95 % relative to the original castor oil.

h- diluting the raw and dry biodiesel with turbo fuel JP A1 at a biodiesel concentration of between 5 and 30 % w/w, preferably at a concentration of between 10 and 20 % in weight, preferably 20 %,

i- adding preferably 500 ppm of a 50 % mixture of C1 to C3 light alcohol, preferably ethanol, with water,

j- keeping this mixture at - 29 °C during 12 hours,

k- centrifuging, preferably at 1200 g for at least 4 minutes,

I- filtering through a 20 micron filter, m- filtering through a 1 micron filter,

Another object of the present invention is a turbo fuel obtained by the described process and its use for formulation of fuels for aviation jet engines, Antarctic fuel oil and gasoil for low temperatures. Optionally, said turbo fuel can comprise tert- butylhydroquinone TBHQ at a preferred concentration of 500 ppm.

Brief description of the figures

Figure 1- Represents a GC chromatogram of dry FAME.

Figure 2- Represents an analysis by ¹H-NMR of FAME of castor oil in CI3CD.

Detailed description of the invention

Obtaining of FAME from castor oil (ricin oil)

The FAME of castor oil is synthesized by transesterification of castor oil with a light alcohol, preferably methanol, using an alkali as catalyst, preferably sodium hydroxide. Commercial castor oil and sodium hydroxide previously dissolved in methanol are reacted. The mixture is let to decant and the glycerin is removed from the inferior portion of the reactor. It is then neutralized with acid, preferably glacial acetic acid, washed with tap water in two stages, incorporating it as an aerosol from above avoiding thus an excessive emulsification. The lower aqueous phase from the second wash is removed in order to obtain raw biodiesel. The remaining water and excess of methanol are eliminated by vacuum distillation. The conversion of castor oil into FAME exceeds 95 % as assessed by ¹H NMR using the β-ΟΗ2 signals at 2.3 (t) assigned to the 100% of the fatty acids and the singlet at 3.7 of the methoxy groups corresponding to FAME (Figure 2).

The castor oil biodiesel thus obtained shows an interesting performance at low temperature but its viscosity imposes a limit in mixtures with JP in order to meet the specifications. Treatment of FAME obtained from castor oil

The described dry biodiesel (FAME) is diluted with turbo fuel JP A1 in a concentration of FAME between 5 and 30 % w/w. A 50% mixture of a C1-C3 light alcohol with water, preferably ethanol, preferably at a concentration of 500 ppm. This mixture is placed at -29°C for 12 hours. Then, it is centrifuged preferably at 1200 g for 4 minutes and it is successively filtered through filters of 20 and 1 microns with a final yield of at least 92%. The retained solid, according to the GC-MS analysis, fundamentally corresponds to methyl stearate and palmitate.

Dilutions of this turbo fuel treated with JP A1 produced the following parameters:

Table 2- - Parameters of FAME:JP A1 mixtures

Preferably, a formulation of turbo fuel of the present invention further contains at least 500 ppm of tert-butylhydroquinone TBHQ.

Stability to oxidation tests of turbo fuels of the invention with a concentration of 30 % in weight of biodiesel in JP A1 (B30) produced an induction time of 20 minutes, said value increased more than 6 hours by adding 500 ppm of TBHQ.

According to the values of the Table 2, it can be seen that even B20 is an adequate concentration to be used as aeronautic fuel (BIOJET) since its viscosity and parameters of low temperature meet the specifications of JP A1.

On the other hand, the informed parameters meet the requirements of the Antarctic fuel oil (BIO GOA) and it is successfully used at the Marambio Base belonging to the Argentine Air Force. After 1200 operating hours, the borescope test performed on the used diesel engine showed a performance equivalent to that obtained with the Antarctic fuel oil derived from oil.

Finally, it is clear that for low temperatures the treated ricin biofuel can partially replace gasoil up to concentrations near to 20 % w/w.

In the present document turbo fuel means a fuel that can be used in plane jet engines.

EXAMPLES

Example 1

Obtaining of FAME from castor oil

The FAME from castor oil was synthesized by transesterification of the castor oil with methanol using sodium hydroxide as a catalyst. The reaction was carried out in a glass reactor of 120 L. 50 L of commercial castor oil and 250 g of sodium hydroxide previously dissolved in 10 L of methanol were reacted during 1 hour at 28 °C. After 12 hours the glycerin decanted (about 3 kg) and was removed from the inferior portion of the reactor. After neutralizing with glacial acetic acid, 120 L of tap water were added in two steps of 60 L each one being incorporated as an aerosol from above avoiding thus an excessive emulsification. The inferior aqueous phase from the second wash was removed after 5 hours, leaving a total volume of 55 L of raw biodiesel. The remaining water and excess of methanol were eliminated by vacuum distillation (20 mm) at 100 °C, using a Lauda equipment with, with a flow rate of 6 L per hour. The performance of dry FAME was 50 L. The analysis of GC-MS in a Perkin-Elmer Q-Mass 910 equipment using a SE-30 column and He as carrier gas is shown in the Figure 1.

The conversion of castor oil to FAME exceeded 95 % assessed by 1 H-NMR using the signals of CH2 β at 2.3 (t) assigned at 100 % of the fatty acids and the singlet at 3.7 of methoxy groups corresponding to FAME (figure 2).

The parameters of the resulting castor oil FAME are shown on the Table 1. Table 1- Parameters of FAME

It can be seen that the castor oil biodiesel shows an interesting performance at low temperature but its viscosity imposes a limit in the mixtures with JP in order to meet the specifications.

Example 2

Treatment of castor oil FAME

The described dry FAME was diluted with 30 % JP A1 w/w, 500 ppm of a 50 % mixture of C1-C3 light alcohol, preferably ethanol, with water were added, keeping at -29 °C for 12 hours. Then it was centrifuged at 1200 g for 4 minutes and successively filtered through a filter of 20 and 1 microns with a final yield of 92 %. The retained solid, according to the GC-MS analysis, fundamentally corresponds to methyl stearate and palmitate.

Example 3

Obtaining of biofuel suitable for low temperatures

Dilutions of this B30 treated with JP A1 presented the following parameters:

Table 2- - Parameters of FAME:JP A1 mixtures

% w/w B20 B15 B10 B5

Water (ppm) <500 <500 <500 <500

Cloud point (CP) °C <-50 <-50 <-50 <-50

Viscosity (20°C) cSt 2.05 1.89 1.73 1.74 Tests of stability to oxidation of B30 showed an induction time of 20 minutes, said value increased more than 6 hours by adding 500 ppm of tert-butylhydroquinone TBHQ.

Claims

1 . A process for obtaining biofuel from castor oil characterized in that it comprises the following steps:

a) reacting by transesterification commercial castor oil, methanol and sodium hydroxide previously dissolved in said methanol at a temperature less than 40 C° and during a maximum time of 60 minutes,

b) decanting,

c) removing glycerin which is the lower phase,

d) neutralizing with acid,

e) washing with water in at least two steps,

f) removing the lower aqueous phase from the last washing in order to obtain raw biodiesel,

g) eliminating the remaining water and the excess of methanol by vacuum distillation and obtaining raw and dry biodiesel,

h) diluting the raw and dry biodiesel with turbo fuel JP A1 at a raw and dry biodiesel concentration of between 5 and 30 % w/w,

i) adding a 50 % mixture of C1 to C3 light alcohol with water,

j) keeping this mixture at - 29 °C during 12 hours,

k) centrifuging,

I) filtering through a 20 micron filter,

m) filtering through a 1 micron filter.

2. The process of claim 1 characterized in that it comprises a maximum ratio between said methanol from step "a" with respect to said castor oil up to 1 :5 (oil volume: methanol volume).

3. The process of claim 1 characterized in that said temperature from step "a" is less than 30 °C.

4. The process of claim 1 characterized in that said acid from step "d" is glacial acetic acid.

5. The process of claim 1 characterized in that the water from step "e" is added as an aerosol from above avoiding thus an excessive emulsification.

6. The process of claim 1 characterized in that said raw and dry biodiesel obtained in step "g" comprises a yield of at least 95 % as compared to the original castor oil.

7. The process of claim 1 characterized because said mixture from the step "i" comprises ethanol as light alcohol.

8. The process of claim 1 characterized in that said mixture from step "i" comprises a concentration of 500 ppm in said dilution of raw and dry biodiesel with JP A1 turbo fuel.

9. The process of claim 1 characterized in that said centrifugation in step "k" comprises centrifuging at 1200 g for at least 4 minutes.

10. The process of claim 1 characterized in that in said step "h" said raw and dry biodiesel is diluted with JP A1 turbo fuel at a concentration of said raw and dry biodiesel of between 10 and 20 % w/w.

1 1. The process of claim 1 characterized in that in said step "h" said raw and dry biodiesel is diluted with JP A1 turbo fuel at a concentration of said raw and dry biodiesel of 20 % w/w.

12. A turbo fuel obtained by the process of the claim 1.

13. The turbo fuel of claim 12 characterized in that it further comprises tert- butylhydroquinone TBHQ.

14. The turbo fuel of claim 13 characterized in that it comprises said tert- butylhydroquinone TBHQ at a concentration of 500 ppm.

15. The use of the turbo fuel of claim 12 for formulation of fuels of aviation jet engines, Antarctic fuel oil and gasoil for low temperatures.

16. A turbo fuel characterized in that it comprises 20 % in weight of raw and dry biodiesel obtained in the step "g" of the claim 1 , JP A1 turbo fuel and tert- butylhydroquinone TBHQ at a concentration of 500 ppm.